[PATCH] Add function to get a single NM D-Bus property (#471812)

[David Cantrell <dcantrell redhat com>]

In order to patch #471812, I needed to read a lot of D-Bus properties.
Created this function to do the work.  Can probably rewrite the
get_connection() function to use this new function too, but I will
save that for a rainy day.
---
 loader/net.c |   71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 loader/net.h |    2 +
 2 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/loader/net.c b/loader/net.c
index aead300..14508c7 100644
--- a/loader/net.c
+++ b/loader/net.c
@@ -2020,4 +2020,75 @@ int get_connection(iface_t *iface) {
     return 9;
 }
 
+/*
+ * Get a specific NetworkManager D-Bus property given the D-Bus interface,
+ * the D-Bus path, and the D-Bus property name.
+ */
+DBusMessage *get_nm_dbus_property(char *interface, char *path, char *property) {
+    char *dbus_interface = NULL;
+    char *dbus_path = NULL;
+    char *dbus_property = NULL;
+    DBusConnection *connection = NULL;
+    DBusError error;
+    DBusMessage *message = NULL;
+    DBusMessage *reply = NULL;
+
+    if ((property == NULL) || (path == NULL) || (interface == NULL)) {
+        fprintf(stderr, "%s (%d): missing required argument\n",
+                __func__, __LINE__);
+        return NULL;
+    }
+
+    dbus_error_init(&error);
+    connection = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
+    if (connection == NULL) {
+        dbus_error_free(&error);
+        fprintf(stderr, "%s (%d): %s: %s\n", __func__, __LINE__,
+                error.name, error.message);
+        return NULL;
+    }
+
+    dbus_interface = strdup(interface);
+    dbus_path = strdup(path);
+    message = dbus_message_new_method_call(dbus_interface,
+                                           dbus_path,
+                                           DBUS_INTERFACE_PROPERTIES,
+                                           "Get");
+    if (!message) {
+        fprintf(stderr, "%s (%d): %s: %s\n", __func__, __LINE__,
+                error.name, error.message);
+        free(dbus_interface);
+        free(dbus_path);
+        return NULL;
+    }
+
+    dbus_property = strdup(property);
+    if (!dbus_message_append_args(message,
+                                  DBUS_TYPE_STRING, &dbus_interface,
+                                  DBUS_TYPE_STRING, &dbus_property,
+                                  DBUS_TYPE_INVALID)) {
+        dbus_message_unref(message);
+        fprintf(stderr, "%s (%d): %s: %s\n", __func__, __LINE__,
+                error.name, error.message);
+        free(dbus_interface);
+        free(dbus_path);
+        free(dbus_property);
+        return NULL;
+    }
+
+    reply = dbus_connection_send_with_reply_and_block(connection, message,
+                                                      -1, &error);
+    dbus_message_unref(message);
+    if (!reply) {
+        fprintf(stderr, "%s (%d): %s: %s\n", __func__, __LINE__,
+                error.name, error.message);
+    }
+
+    dbus_connection_unref(connection);
+    free(dbus_interface);
+    free(dbus_path);
+    free(dbus_property);
+    return reply;
+}
+
 /* vim:set shiftwidth=4 softtabstop=4: */
diff --git a/loader/net.h b/loader/net.h
index 8245084..25708fb 100644
--- a/loader/net.h
+++ b/loader/net.h
@@ -20,6 +20,7 @@
 #ifndef H_LOADER_NET
 #define H_LOADER_NET
 
+#include <dbus/dbus.h>
 #include <newt.h>
 #include "../isys/iface.h"
 #include "loader.h"
@@ -73,5 +74,6 @@ int kickstartNetworkUp(struct loaderData_s * loaderData,
                        iface_t * iface);
 void splitHostname (char *str, char **host, char **port);
 int get_connection(iface_t * iface);
+DBusMessage *get_nm_dbus_property(char *interface, char *path, char *property);
 
 #endif
-- 
1.6.0.3